December 14, 1906.] 



SCIENCE. 



781 



tinguishing feature of the genus. Many skulls 

 were found, but unfortunately no single one 

 was complete. They were found in a very 

 limited area, and together with them were 

 great numbers of rhinoceros bones, many of 



Syndyocsras, Oxydactylus, a species of horse, 

 tapir, rhinoceros, etc., being associated consti- 

 tute an interesting new fauna for the region. 



Dental formula: I 1/?, C ?/0, P 4/3, M 3/3. 



Measurements: Length of skull, 375 mm. 



Fig. 1. Skull of Diceratherium arikarense, side view, drawn from a specimen in the collections 



of Hon. Charles H. Morrill. 



Top view of the above 



which presumably belong to this genus, in 

 which event a complete restoration is assured. 

 The mandible is strong, and its angles are ex- 

 panded and flare outward. Some crania are 

 so short and saddle-shaped that they must be- 

 long properly to another speciesi 



Diceratherium^ Elotherium, Chalicotherium, 



(14.75 inches) ; extreme width across zygoma, 

 220 mm. (8.75 inches) ; distance between post- 

 orbital processes, 130 mm. (5 inches) ; width 

 across horn cores, 68 mm. (2.75 inches). 



Erwin Hinckley Barbour. 

 The Univeesity of Nebraska, 

 July 4, 1906. 



